Problems maintaining a stable temperature

I have noticed that my nano reef's temperature fluctuates over the day. It ranges from 76 with the heater and light off to 83 with the heater and light on. If I leave the heater off, the light is able to heat the tank to about 80. I know an 8 degree swing is not a good thing, and I have a couple options. Should I look at a different heater or swap out the light for an LED version. What do you guys think?

This is probably the biggest issue with a small tank. LED's should probably help reduce heat during the day. You could just try to add a fan that runs with the lights, a small computer fan would work. The other option is to raise the temperature of the tank runs with the lights off to reduce the swing. The biggest issue with high temperatures is that warmer water cannot hold the same amount of oxygen as the cooler water so fish can suffocate.

You could post some pics and info on the setup for us to help you better.